BBC Wild - Mighty Amazon

BBC Wild South America 2of6 Mighty Amazon

The second programme shows how life along the Amazon River is dominated by the annual cycle of floods. In the dry season, female giant river turtles gather on exposed sand banks to lay their eggs. As broad reaches of river are cut off by sandbars, caimans and egrets take advantage of the bounty of fish trapped in shallow lagoons. Underwater infrared cameras film scavenging candiru and an electric eel hunting. As the first rains arrive, a cormorant flock feeds quickly to take advantage before the fish begin to disperse. Black vultures get an easy meal as fish killed by oxygen-starved water wash up on the river banks. In the rainy season, water levels along the Amazon can rise up to 10m. Invertebrates emerge from cover in the undergrowth and migrate into the trees to escape drowning, but lizards and praying mantises await their arrival. Fire ants mass into a floating raft to move from their flooded nests, while sloths and tarantulas have adapted to swimming between trees. Predators are at a disadvantage now, but giant otters are expert hunters and use teamwork to corral fish. The boto, a rare river dolphin, navigates the submerged forests using sonar. Rainforest trees, which can survive inundation for six months, time their fruiting to coincide with the floods, using fish as seed dispersers. Villages and communities line the river's banks, but their overall environmental impact is low and they have adapted to the annual cycle of flooding. The sheer scale of the Amazon may yet ensure its survival